(1) Field of the Invention
The present invention relates to work platform assemblies and more particularly to such assemblies which may be used to machine the interior surface of a tubular object.
(2) Description of the Prior Art
Various devices are disclosed in the prior art for providing access to cylindrical tubular recessed work surfaces. For example:
U.S. Pat. No. 3,058,543 to Prosser discloses a portable scaffold deployed in a vessel. This apparatus makes use of a radially extendable stabilizing arms and expandable width grating.
U.S. Pat. No. 3,870,122 to Faucheux discloses a catwalk that spans the circumference of a dome structure. The apparatus includes a roller track at the end of the catwalk on the side of the roller track which is movable thereon.
U.S. Pat. No. 3,960,242 to Saxonmeyer discloses an orbital service bridge for positioning a work platform at desired positions within an overlying dome shaped structure. Included in the apparatus is a polar crane which has parallel guide rails spanning a cylindrical vessel.
U.S. Pat. No. 5,067,589 to Bartnicki discloses an extendable platform in which two platform sections can be nested or moved apart from one another to increase platform length.
U.S. Pat. No. 5,301,770 to Regan et al. discloses an adjustable work platform assembly for the inside c)f a vessel. The platform is suspended from above and is extendable and collapsible to fit the various diameters of the vessel.
A need, however, exists for a device which can easily machine the interior surface of a tubular cylindrical recessed surface.